Influence of rice husk on biological efficiency and nutrient content of Pleurotus ostreatus (Jacq. ex. Fr.) Kummer

Rice husk was evaluated as a possible additive to composted sawdust of Triplochiton scleroxylon to ascertain its contribution to the biological efficiency (BE) and nutrient content of Pleurotus ostreatus (Jacq. ex. Fr.) Kummer. Mycelial growth rate, spawn run period and mean number of fruit body per flush were the other parameters studied. The BE values on the different rice husk concentrations (2, 5, 10, 15 and 20%) were 75.2, 64.0, 49.6, 43.3 and 40.7% respectively indicating an 11% increase over the control at 2% concentration. The mean mycelial growth rate and the spawn run period on the substrate showed an increasing trend with increasing rice husk concentration. Major mineral constituents of fruit body of the mushroom such as Ca and P and proximate analysis of fat, ash and carbohydrate content also showed significant increases (P 0.05) over the control. Based on these increases in both the BE and proximate composition of Pleurotus ostreatus strain EM-1, rice husk at 2% concentration can be used as an alternate additive for producing more nutritious mushrooms.